Dumping devices are generally used to transport loads, or to temporarily store loads. Such devices usually consist of a container attached to a support structure. They may be small scale devices, such as the garden carts used to transport such items as dirt, leaves, and grass clippings. On a larger scale, dumping devices encompass wheelbarrows used by construction workers to carry materials such as concrete, bricks, and rocks. Although some dumping devices are wheeled carriers, others are not, i.e., containers in which concrete may be mixed prior to its unloading.
Most prior known dumping devices require that the support structure to which the container is attached be lifted from one end in order to dump the contents of the container. In the case of manually operated dumping devices, this may require a great deal of strength on the part of the operator. Such activity may become physically hazardous. Even where the dumping device is mechanically operated, emptying the container may still consume a great amount of energy.
Dumping devices wherein the container may rotate relative to the support structure are known in the art. Most of these inventions still require the operator or operating means to overcome the force of gravity when causing the container to dump its load. The dumping hand cart disclosed in U.S. Pat. No. 3,178,228 makes some use of a gravitationally unbalanced container which may be more easily rotated. However, the disclosure teaches a device which pushes the container from behind its center of gravity, and thus does not take full advantage of the container's unstable position. Similarly, the dumping wheelbarrow disclosed in U.S. Pat. No. 3,092,418, while also employing a gravitationally unbalanced container, discloses a rigid rod which pulls on the container. Because of the structure of the rod and the relatively small torque it generates, that invention is mechanically and ergonomically inefficient.
In contrast, the present invention utilizes a container maintained in an unstable rotational equilibrium, where the rotation of the container is controlled by an actuator exerting a force forward and above the center of gravity of the container. This results in a device which requires little force to initiate forward rotation of the container, as well as a more efficient means of controlling the container's rotation. Further, this device encompasses a number of actuators, such as a rotatably connected lever and link system, which increase ergonomic efficiency.